Rainwater is used as an energy supply for the whole system. As rainwater flows through the downpipes, it turns a water wheel which in turn turns a dynamo via an axle. The other side of the dynamo is connected to rechargeable alkaline batteries via electrical cables. In this way, rainwater is used to generate small amounts of electricity.

How does it work?

Conversion of Energy

As rainwater flows through the down pipe, it causes the water wheel to turn. At the top of the pipe, the water has gravitational potential energy. As it flows down, this energy is converted to mechanical energy as the wheel turns.

There is an axle attached to the wheel which turns when the wheel spins. The other side of the axle is connected to a dynamo which generates electricity when the axle causes it to turn. Mechanical energy is converted to electrical energy.

Design

The dynamo will generate current that is alternating current (AC) in nature so it must go through a rectifier circuit before being transferred to the rechargeable alkaline batteries which can only be charged with a direct current (DC). The rectifier circuit converts the AC current into DC.

Parallel capacitors are used to stablise any oscillations while the diode is used to prevent the batteries from discharging.